How to write lambda as def function?

Question

How do I write the below lambda function as a def function?

df['hourly'] = df['Salary Estimate'].apply(lambda x: 1 if 'per hour' in x.lower() else 0)

Answer 1

def fun(x):
   return 1 if 'per hour' in x.lower() else 0

then

df['hourly'] = df['Salary Estimate'].apply(fun)

Answer 2

def my_super_fun(x):
    return 1 if 'per hour' in x.lower() else 0
df['hourly'] = df['Salary Estimate'].apply(my_super_fun)

You can pass any one-argument function to apply function.